Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • Medical
  • When radiation of wavelength  is incident on a metallic surface, the stopping potential is <img alt="4.8" s

When radiation of wavelength \lambda is incident on a metallic surface, the stopping potential is 4.8 volts. If the same surface is illuminated with radiation of double the wavelength, then the stopping potential becomes 1.6 volts. Then the threshold wavelength for the surface is -

Option: 1

2\lambda


Option: 2

4\lambda


Option: 3

6\lambda


Option: 4

8\lambda


Answers (1)

best_answer

\begin{aligned} & V_0=\frac{h c}{e \lambda}-\frac{W}{e} \\ & 4.8=\frac{h c}{e \lambda}-\frac{W}{e} \end{aligned}                                           .........................\left ( 1 \right )
1.6=\frac{\mathrm{hc}}{2 \mathrm{e} \lambda}-\frac{\mathrm{W}}{\mathrm{e}}                                         ..........................\left ( 2 \right )
\begin{aligned} & \frac{\mathrm{eq}^{\mathrm{n}}(1)}{\mathrm{eq}^{\mathrm{n}}(2)} \Rightarrow \frac{4.8}{1.6}=\frac{\frac{\mathrm{hc}}{\mathrm{e} \lambda}-\frac{\mathrm{W}}{\mathrm{e}}}{\frac{\mathrm{hc}}{2 \mathrm{e} \lambda}-\frac{\mathrm{W}}{\mathrm{e}}} \\ & \frac{3 \mathrm{hc}}{2 \mathrm{e} \lambda}-\frac{3 \mathrm{~W}}{\mathrm{e}}=\frac{\mathrm{hc}}{\mathrm{e} \lambda}-\frac{\mathrm{W}}{\mathrm{e}} \\ & \text { or } \frac{2 \mathrm{~W}}{\mathrm{e}}=\frac{\mathrm{hc}}{2 \mathrm{e} \lambda} \\ & \text { or } \frac{2}{\mathrm{e}}\left(\frac{\mathrm{hc}}{\lambda_0}\right)=\frac{\mathrm{hc}}{2 \mathrm{e} \lambda} \\ & \Rightarrow \lambda_0=4 \lambda \end{aligned}

Posted by

Pankaj Sanodiya

View full answer

NEET 2024 Most scoring concepts

    Just Study 32% of the NEET syllabus and Score up to 100% marks

Similar Questions

Trending Articles/News

anam-khan

CBI arrests Latur coaching centre founder in NEET-UG paper leak case; exam questions found on phone
anam-khan

NEET UG ‘Paper Leak’: CBI conducts searches at Renukai Chemistry Classes in Latur
anam-khan

Abolish NEET, restore state CET; Karnataka urges Centre after paper leak row

Latest Question